Pecan nut casebearer (Acrobasis nuxvorella) is a serious insect pest against pecans, which tunnels into pecan nuts and feeds in the nuts. The use of insecticides for pest control on the pecan nut casebearer may lead to outbreak of secondary insect pests, such as aphids, mites and leaf-miner flies, because the insecticides also kill natural enemies of such secondary insect pests. Therefore, a large hope is placed on mating disruption using a sex pheromone.
(9E,11Z)-9,11-Hexadecadienal and (9E,11Z)-9,11-hexadecadienyl acetate were identified as components of natural sex pheromones of the pecan nut casebearer (Non-Patent Literatures 1 and 2).
Millar et al. describes a process for preparing (9E,11Z)-9,11-hexadecadienal, in which a vinyl iodide derived from 9-decyn-1-ol is subjected to the Sonogashira coupling with 1-hexyne, followed by alcohol protection, hydroboration and subsequent protonation, removal of a protecting tetrahydropyranyl (THP) group for the hydroxy group, and oxidation (Non-Patent Literature 1). Harris et al. describes another process for preparing (9E,11Z)-9,11-hexadecadienal, in which (1E)-1-chloro-1-octen-3-yne, which has been obtained by the Sonogashira coupling of (E)-1,2-dichloroethene with 1-hexyne, is subjected to the Kochi-Fürstner coupling with 1-(tetrahydropyranyloxy)-8-bromooctane derived from 1,8-octanediol to obtain (9E)-1-(tetrahydropyranyloxy)-9-hexadecen-11-yne, followed by hydroboration and subsequent protonation, removal of a protecting THP group, and oxidation (Non-Patent Literature 2).